Six months after this post,i guess its not only bitcoin who makes investors here a billionaires because altcoins and tokens are best engines to make good profit,thats why hundreds or thiusands of ICO are running day by day.
Yes bitcoin has the highest value but many alt and tokens that if you gather together are more valuable than the Top coin.
That wealth is distrubuted unequally between thousands of people so the number of of billionaires is less than the number of multi-millionaires and the number of multi-millionaires is less than the number of millionaires and so on...
Cryptocurrencies as you mentioned are doing very well, ICOs are still running and tokens are still available but the thread was started to discuss Bitcoin billionaires. No problem, if you know of any Ethereum or XRP or any altcoin billionaires please list them here.